A multilayer circuit board comprises a plurality of wiring substrates, and sometimes some of the wiring substrates need to be tinned.
At present, an opening is defined in the multilayer circuit board to expose the region that needs to be tinned, and then a tinning process is applied on the region to form a tin layer. The adhesive layers, the solder mask, and the wiring layer of the multilayer circuit board are exposed from the opening. When the tinning process is applied on the multilayer circuit board, the exposed adhesive layers, the exposed solder mask, and the exposed wiring layer may be damaged by Galvanic Corrosion which may result in a decrease in the stability of the multilayer circuit board. Therefore, there is room for improvement within the art.